JP2008101286A - Biodegradable face cover - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable face cover including a nonwoven fabric obtained by a spun-bonding method owing to good spinnability and openability, wherein the nonwoven fabric has excellent softness, causes little shrinkage in the post-processing of the nonwoven fabric and disposable to form a compost after use. <P>SOLUTION: The face cover is composed of a nonwoven fabric produced by using a conjugate filament including a polylactic acid polymer and an aliphatic polyester copolymer having a melting point lower than that of the polylactic acid polymer as a constituent fiber. The aliphatic polyester copolymer forms at least a part of the surface of the constituent fiber. The aliphatic polyester copolymer includes an aliphatic diol, an aliphatic dicarboxylic acid and an aliphatic hydroxycarboxylic acid as constitution components, and is crosslinked. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a biodegradable face cover for covering a face when clothes are attached and detached.

When a person who puts makeup on the face attaches or detaches the clothes, if the clothes come into contact with the face, the makeup is disturbed and the clothes become dirty due to the adhesion of the cosmetic.
In order to solve such a problem, a bag-shaped face cover that covers the head including the face when clothes are attached and detached has been proposed (Patent Documents 1 and 2). Each of the face covers proposed in Patent Documents 1 and 2 is made of a nonwoven fabric.
JP 2000-125934 A JP 2006-087789 A

  The present invention further improves the conventional face cover described above, and has good yarn-making properties and spreadability, so that it can be made into a nonwoven fabric by the spunbond method, and the obtained nonwoven fabric is flexible. An object of the present invention is to provide a biodegradable face cover that is excellent, has little shrinkage in post-processing of a nonwoven fabric, and can be composted after use.

  As a result of intensive studies to solve the above problems, the inventors have obtained knowledge that the above problems can be solved by using a specific polymer as an adhesive component and a specific fiber cross section, The present invention has been reached.

  That is, the means for solving the above-described problems are as follows.

  (1) A non-woven fabric comprising a composite long fiber containing a polylactic acid polymer and an aliphatic polyester copolymer having a melting point lower than that of the polylactic acid polymer, and the aliphatic polyester copolymer is It forms at least a part of the surface of the constituent fiber, and the aliphatic polyester copolymer includes an aliphatic diol, an aliphatic dicarboxylic acid, and an aliphatic hydroxycarboxylic acid as constituent components and is crosslinked. A biodegradable face cover.

(2) The biodegradable face according to (1), wherein the basis weight is 15 to 50 g / m ² , the flexibility is 15 cN or more and 60 cN or less, and the drape coefficient is 0.650 or more and 0.950 or less. cover.

  (3) In the crosslinked aliphatic polyester copolymer, the aliphatic diol is 1,4-butanediol, the aliphatic dicarboxylic acid is succinic acid, the aliphatic hydroxycarboxylic acid is lactic acid, and its melting point is The biodegradable face cover according to (1) or (2), wherein the biodegradable face cover is at least 50 ° C. lower than the melting point of the polylactic acid polymer.

  (4) When the composite continuous fiber is melted at a rate of temperature increase of 10 ° C./min and then subjected to differential thermal analysis at a rate of temperature decrease of 10 ° C./min, there is a temperature decrease crystallization temperature due to the aliphatic polyester copolymer. The temperature-falling crystallization temperature is 75 ° C. or more and 85 ° C. or less, and the composite long fiber has a crystallization heat amount of 20 J / g or more and 30 J / g or less, wherein (1) to (3) Any biodegradable face cover.

  The biodegradable face cover of the present invention comprises a nonwoven fabric comprising a composite long fiber comprising a polylactic acid polymer and an aliphatic polyester copolymer having a melting point lower than that of the polylactic acid polymer, The aliphatic polyester copolymer forms at least part of the surface of the constituent fiber, and the aliphatic polyester copolymer comprises an aliphatic diol, an aliphatic dicarboxylic acid, and an aliphatic hydroxycarboxylic acid as constituent components. In addition, since it is cross-linked, it has good spinning properties and spreadability, and therefore can be made into a non-woven fabric by the spunbond method, and the face cover obtained from this non-woven fabric has excellent flexibility, Even during processing such as heat sealing when forming a nonwoven fabric into a bag-shaped face cover, there is little shrinkage and composting can be performed after use.

  The biodegradable face cover of the present invention comprises a polylactic acid polymer as a constituent component of a non-woven fabric, and an aliphatic polyester copolymer as a thermal adhesive component having a lower melting point than the polylactic acid polymer. Including.

First, the polylactic acid polymer will be described.
Examples of the polylactic acid polymer used in the present invention include poly-D-lactic acid, poly-L-lactic acid, a copolymer of D-lactic acid and L-lactic acid, and a copolymer of D-lactic acid and hydroxycarboxylic acid. A polymer selected from the group consisting of a polymer, a copolymer of L-lactic acid and hydroxycarboxylic acid, a copolymer of D-lactic acid, L-lactic acid and hydroxycarboxylic acid, or a blend thereof. Can be mentioned. Examples of the hydroxycarboxylic acid include glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, and the like. Among these, hydroxycaproic acid and glycolic acid are particularly preferable from the viewpoint of decomposition performance and low cost.

  In the present invention, it is preferable to use a polylactic acid polymer having a melting point of 150 ° C. or higher or a blend thereof. When the melting point of the polylactic acid-based polymer is 150 ° C. or higher, since it has high crystallinity, shrinkage during heat treatment is less likely to occur, and heat treatment can be performed stably. Since the obtained long fiber nonwoven fabric has excellent heat resistance, it is practical during transportation and storage.

  The melting point of poly-L-lactic acid and poly-D-lactic acid, which are homopolymers of polylactic acid, is about 180 ° C. When a copolymer is used as the polylactic acid polymer instead of a homopolymer, the copolymerization ratio of the monomer components is determined so that the melting point of the copolymer is 150 ° C. or higher. For this purpose, for example, in the case of a copolymer of L-lactic acid and D-lactic acid, the copolymerization ratio of L-lactic acid and D-lactic acid is (L-lactic acid) / (D -Lactic acid) = 5 / 95-0 / 100, or (L-lactic acid) / (D-lactic acid) = 95 / 5-5 / 100. When the copolymerization ratio is out of the above range, the copolymer has a melting point of less than 150 ° C., and thus the amorphous property becomes high and the object of the present invention may not be achieved.

  Next, an aliphatic polyester copolymer having a lower melting point than the polylactic acid polymer will be described. This aliphatic polyester copolymer has an aliphatic diol, an aliphatic dicarboxylic acid, and an aliphatic hydroxycarboxylic acid as constituent components.

  Aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedi Methanol etc. are mentioned. These may be used alone or a mixture thereof may be used. In consideration of the physical properties of the obtained copolymer, it is preferable to use 1,4-butanediol.

  Examples of the aliphatic dicarboxylic acid include oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, suberic acid, dodecanedioic acid, and the like, and acid anhydrides that are derivatives thereof may be used. Considering the physical properties of the resulting copolymer, succinic acid or succinic anhydride, or a mixture of these with adipic acid is preferable.

  Examples of the aliphatic hydroxycarboxylic acid include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 2-hydroxyisocaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, and 2-hydroxy-3. -Methyl lactic acid, leucine acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, methyl lactic acid, caprolactone, valerolactone and the like. Two or more of these aliphatic hydroxycarboxylic acids may be used in combination.

  Further, when an optical isomer is present in the aliphatic hydroxycarboxylic acid, any of D-form, L-form or racemic form may be used, and the aliphatic hydroxycarboxylic acid is a solid, liquid or oligomer. There may be.

  As the aliphatic polyester copolymer, specifically, an aliphatic polyester copolymer in which the aliphatic diol is 1,4-butanediol, the aliphatic dicarboxylic acid is succinic acid, and the aliphatic hydroxycarboxylic acid is lactic acid, A copolymer obtained by copolymerizing lactic acid with butylene succinate can be preferably used. As such an aliphatic polyester copolymer, it is preferable to use what is described in patent 3402006 specification, for example. As such an aliphatic polyester copolymer, specifically, trade name “GSPla (crystal melting point 110 ° C.)” manufactured by Mitsubishi Chemical Corporation can be preferably used. When this “GSPla” is used, since the aliphatic polyester copolymer is copolymerized with lactic acid, the compatibility with the polylactic acid polymer is improved. Therefore, composite spinning can be performed satisfactorily in the melt spinning process. In addition, in order to improve the thermal adhesiveness at the time of making the nonwoven fabric and to improve the heat sealability of the obtained nonwoven fabric, the melting point difference between the polylactic acid polymer and the aliphatic polyester copolymer is 50 ° C. or more. It is preferable that

  In the aliphatic polyester copolymer, it is necessary to melt and mix the organic peroxide at the raw material stage, whereby crosslinking is performed and the crystallization speed of the aliphatic polyester copolymer is increased. For this reason, aliphatic polyester copolymers can be used in spunbonded nonwoven fabric manufacturing processes, where the distance from the spinning process to the cooling / stretching process is limited compared to the manufacturing process of short fiber nonwoven fabrics. It can be cooled and crystallized well. Thereby, generation | occurrence | production of the blocking in a fiber opening process can be prevented effectively.

  When the organic peroxide is heated at a rate of 4 ° C./min with an electric heating plate at a rate of 4 ° C./min (rapid heating test), the temperature at which decomposition starts (decomposition temperature) is 90 ° C. or higher and 200 ° C. or lower. preferable. When the decomposition temperature is higher than 200 ° C., it is difficult to generate radicals at the time of melt mixing with the aliphatic polyester, and the aliphatic polyester is less likely to cause a crosslinking reaction. On the other hand, if the decomposition temperature is lower than 90 ° C., the organic peroxide is likely to generate radicals before being sufficiently dispersed in the aliphatic polyester, so that a local reaction occurs and a uniform crosslinking reaction product is obtained. Sometimes there is a local explosive reaction. Since this decomposition temperature also changes depending on the purity of the organic oxide, it is possible to change the purity of the composition containing the organic peroxide, that is, the organic peroxide composition, within the above range. is there.

  Specific examples of organic peroxides include benzoyl peroxide, bis (butylperoxy) trimethylcyclohexane, bis (butylperoxy) cyclododecane, butylbis (butylperoxy) valerate, dicumyl peroxide, butylperoxybenzoate , Dibutyl peroxide, bis (butylperoxy) diisopropylbenzene, dimethyldi (butylperoxy) hexane, dimethyldi (butylperoxy) hexyne, butylperoxycumene and the like.

  The blending amount of the organic peroxide in the melt mixing is preferably 0.01 to 1 part by weight, more preferably 0.01 to 0.5 part by weight with respect to 100 parts by weight of the aliphatic polyester copolymer. More preferred is 0.01 to 0.3 parts by mass. If the amount is less than 0.01 parts by mass, the required effect of improving the crystallization rate is difficult to be exhibited. If the amount exceeds 1 part by mass, the viscosity of the copolymer becomes high and the spinnability during melt spinning tends to be inferior.

  In connection with the above points, the aliphatic polyester copolymer melt-mixed with the organic peroxide is heated to 200 ° C. at a temperature rising rate of 500 ° C./min using a DSC apparatus in the raw material stage, Hold for 5 minutes in the molten state and melt, then cool down to 90 ° C at a cooling rate of 500 ° C / min, hold at 90 ° C to cause isothermal crystallization, and the differential crystallization rate index is 3 minutes or less It is preferable that This crystallization rate index is the time (minutes) required to reach one half of the degree of crystallinity finally reached when the polymer is cooled from the molten state at 200 ° C. and crystallized at 90 ° C. The smaller the index, the faster the crystallization rate. Therefore, as an aliphatic polyester copolymer used as a raw material for the composite fiber, a high crystallization rate index of 3 minutes or less can be used to improve the cooling property when melt-spun. It is possible to make it difficult to cause blocking at the time of fibering.

  The present inventors presume that the reason why the crystallization rate of the aliphatic polyester copolymer as a raw material in the present invention is increased by crosslinking is as follows. That is, when an organic peroxide is melt-mixed with the aliphatic polyester copolymer, a cross-link is formed in the copolymer, and this cross-linked portion functions as a nucleating agent that promotes crystallization, and the crystallization speed is increased. Estimated to be faster.

  In the present invention, the aliphatic polyester copolymer forms at least a part of the surface of the composite fiber. As a fiber cross-sectional form for constituting such a fiber, for example, a side-by-side type composite cross-section in which a polylactic acid polymer and an aliphatic polyester copolymer are bonded together, a polylactic acid polymer forms a core and fat. Core-sheath type composite cross section in which an aliphatic polyester copolymer forms a sheath, a split type composite cross section in which a polylactic acid polymer and an aliphatic polyester copolymer are alternately present on the fiber surface, or a multileaf type composite cross section Etc. Since the aliphatic polyester copolymer plays a role as a thermal adhesive component as will be described later, the core-sheath composite in which the aliphatic polyester copolymer forms the entire surface of the fiber in consideration of this point. A cross section is preferred.

  The polylactic acid polymer forms the core as a fiber-forming component, and the aliphatic polyester copolymer functions as a thermal adhesive component for maintaining the nonwoven fabric form and for bonding with other members by heat sealing In the case of the core-sheath type composite cross section in which the sheath part is formed, the composite ratio (mass ratio) of the core part and the sheath part is preferably core part / sheath part = 3/1 to 1/3. If the ratio of the core part exceeds 3/1, the ratio of the sheath part becomes too small, so the thermal bonding performance tends to be inferior, and the shape retention and mechanical performance of the long-fiber nonwoven fabric tend to be inferior. It becomes difficult to obtain a good heat sealability. On the other hand, when the ratio of the core is less than 1/3, the mechanical strength of the obtained nonwoven fabric tends to be insufficient.

  It is also a preferable condition in the present invention to select a polymer viscosity suitable for high speed spinning. That is, the viscosity of the polylactic acid-based polymer is abbreviated as “MFR1”, which is a melt flow rate measured at a temperature of 210 ° C. and a load of 20.2 N (2160 gf) in accordance with the method described in ASTM-D-1238. ) Is preferably 10 to 80 g / 10 min, more preferably 20 to 70 g / 10 min. When the MFR1 is less than 10 g / 10 minutes, the viscosity is too high, and the burden on the screw at the time of melting in the manufacturing process increases. On the other hand, when MFR1 exceeds 80 g / 10 min, the viscosity is too low, and yarn breakage tends to occur frequently in the spinning process, and the operability tends to be impaired.

  On the other hand, the viscosity of the aliphatic polyester copolymer is a melt flow rate (hereinafter abbreviated as “MFR2”) measured at a temperature of 190 ° C. and a load of 20.2 N (2160 gf) according to the method described in ASTM-D-1238. Is preferably 20 to 45 g / 10 min. When MFR2 is less than 20 g / 10 min, when an organic peroxide is melt-mixed with an aliphatic polyester copolymer, crosslinking is performed thereby, resulting in a polymer having high viscosity. In the process, it is difficult to withstand the stretching tension, and yarn breakage is likely to occur. On the other hand, when the MFR2 exceeds 45 g / 10 min, the degree of polymerization of the aliphatic polyester copolymer is small, so that even if the organic peroxide is melt-mixed, a sufficient crosslinking reaction is not performed, and thus it was obtained. It becomes difficult to obtain a crystallization rate sufficient to sufficiently cool the polymer in the spunbond spinning process.

  The viscosity of the polymer obtained by melt-mixing the aliphatic polyester copolymer and the organic peroxide is 210 ° C. under a load of 20.2 N (2160 gf) in accordance with the method described in ASTM-D-1238. Melt flow rate (hereinafter abbreviated as “MFR5”) measured at a melt flow rate (hereinafter abbreviated as “MFR4”) of 10 to 30 g / 10 min, a temperature of 230 ° C. and a load of 20.2 N (2160 gf). Is preferably 20 to 45 g / 10 min. In this way, defining a plurality of values of MFR4 and MFR5 at different temperatures makes it difficult to confirm the degree of cross-linking with only one MFR value under one temperature condition, and it is possible to correctly confirm the degree of cross-linking for the first time with a plurality of MFR values. Because. If the MFR4 at a temperature of 210 ° C. is less than 10 g / 10 min, the degree of cross-linking of the melt-mixed polymer becomes strong, and thus rubber elasticity is exhibited in the melt spinning process, and the yarn cannot withstand the stretching tension. Thread breakage is likely to occur. On the other hand, when the MFR5 at a temperature of 230 ° C. exceeds 45 g / 10 min, the degree of crosslinking of the melt-mixed polymer is weakened, so the crystallization rate is low, and therefore the yarns adhere closely in the fiber opening process. This may result in a nonwoven fabric with poor formation. A more preferable range of MFR4 and MFR5 is 20 to 30 g / 10 min in both cases. By setting it as such a more preferable range, all of a spinning process, an extending | stretching process, and a fiber opening process can be performed without a problem, and a nonwoven fabric with favorable formation can be obtained.

  In the following, the viscosity of a polymer obtained by melt-mixing an aliphatic polyester copolymer and an organic peroxide is a temperature of 190 ° C. and a load of 20.2 N (in accordance with the method described in ASTM-D-1238. The melt flow rate (hereinafter abbreviated as “MFR3”) measured at 2160 gf) may be used.

  The single yarn fineness of the composite fiber constituting the nonwoven fabric in the present invention is preferably 2 to 7 dtex. Polymers prepared by melting and mixing organic peroxides with aliphatic polyester copolymers have high viscosity due to cross-linking, so if the single yarn fineness is less than 2 dtex, the spun yarn cannot withstand the drawing tension in the spinning process. Thread breakage frequently occurs and operability is likely to deteriorate. On the other hand, when the single yarn fineness exceeds 7 decitex, when the face cover is worn, it comes to feel hardness when it comes into contact with the skin, and it becomes easy to remember discomfort during wearing. For these reasons, the single yarn fineness is more preferably 3 to 5 dtex.

The basis weight of the biodegradable face cover of the present invention is preferably in the range of 15 to 50 g / m ² . If the basis weight is less than 15 g / m ² , the mechanical properties tend to be poor in practicality. On the other hand, when the basis weight exceeds 50 g / m ² , since the constituent fibers are dense in the nonwoven fabric, the texture tends to become hard.

  The biodegradable face cover of the present invention preferably has a flexibility of 15 cN or more and 60 cN or less measured according to the handle ohm method described in JIS L 1906: 2000. When the flexibility exceeds 60 cN, the texture of the nonwoven fabric becomes hard and is not preferable as a face cover.

  The biodegradable face cover of the present invention preferably has a drape coefficient of 0.950 or less measured according to the method described in JIS L 1096: 1999. This drape coefficient represents the drape property (one of the indices of flexibility) of the nonwoven fabric constituting the face cover of the present invention, and the smaller the value, the better the drape property appears. In the present invention, the lower limit of the drape coefficient is about 0.650. This is because if the value is too small, the face cover is too cluttered when the face cover is attached.

As described above, the single yarn fineness of the polylactic acid-based long fiber is 3 to 5 dtex, and the basis weight of the face cover is 15 to 50 g / m ^2. Obtainable.

  In the biodegradable face cover of the present invention, when the composite long fibers constituting the nonwoven fabric are melted at a temperature rising rate of 10 ° C./min and then subjected to differential thermal analysis at a temperature falling rate of 10 ° C./min, The temperature-falling crystallization temperature Tcc caused by the crosslinked aliphatic polyester copolymer as a component exists, the temperature-falling crystallization temperature Tcc is 75 ° C. or more and 85 ° C. or less, and the crystallization heat amount Hexo is 20 J / g or more and 30 J / g. g or less. The temperature drop crystallization temperature Tcc indicates, for example, the temperature at which the seal portion cools and solidifies when heat sealing is performed to produce a bag-shaped face cover. The lower the temperature, the longer the cooling time. In addition, the amount of heat of crystallization Hexo is an ability required for cooling, and when this value is small, a phenomenon occurs in which the heat seal portion does not readily cool and solidify. In the present invention, the use of a crosslinked aliphatic polyester copolymer as a thermal adhesive component enables the temperature-falling crystallization temperature Tcc to be set higher than that of an uncrosslinked aliphatic polyester copolymer, and the crystallization The amount of heat Hexo also increases, that is, when the temperature-falling crystallization temperature Tcc and the amount of heat of crystallization Hexo are in the above ranges, and thus heat sealing is performed to manufacture the face cover of the present invention, the heat-sealed portion is cooled and solidified. Will be faster and productivity will be improved.

Next, based on an Example, this invention is demonstrated concretely. However, the present invention is not limited only to these examples.
In addition, measurement of various physical property values and evaluation of various physical properties in the following examples and comparative examples were performed by the following methods.

  (1) Melting point (° C.): Using a differential scanning calorimeter (manufactured by Perkin Elma, DSC-2 type), the sample mass was measured at 5 mg and the heating rate was 10 ° C./min. The temperature giving the maximum value of the curve was defined as the melting point (° C.).

  (2) Decreasing crystallization temperature Tcc (° C.), crystallization heat amount Hexo (J / g): using a differential scanning calorimeter DSC-7 manufactured by Perkin Elma, the sample mass is 10 mg, and the heating rate is 10 ° C. The temperature giving the extreme value of the exothermic peak of the crystallization exothermic curve obtained when the temperature was raised to 210 ° C./min and then the rate of temperature reduction was 10 ° C./min was defined as the temperature-falling crystallization temperature Tcc (° C.). The area of the exothermic peak portion was defined as the crystallization heat amount Hexo (J / g).

  (3) Fineness (decitex): The fiber diameter in the web state was measured with 50 optical microscopes, and the average value obtained by correcting the density was defined as the fineness.

(4) Weight per unit area (g / m ² ): Ten sample pieces having a sample length of 10 cm and a sample width of 5 cm were prepared from a sample in a standard state, adjusted to equilibrium moisture, and the weight (g) of each sample piece was weighed. And the average value of the obtained value was converted per unit area, and it was set as the basis weight (g / m ² ).

  (5) Flexibility (cN): Measured according to the handle ohm method described in JIS L1906: 2000.

  (6) Drape coefficient: measured according to the method described in JIS L 1096: 1999.

(7) Wearability of the face cover: The wearability when the face cover was worn was subjected to sensory evaluation in the following two stages.
○: Flexibility and draping properties were maintained, and the face cover was kept attached to the head with almost no displacement, and the face was not exposed due to displacement. Moreover, when the detached clothes were observed, adhesion of cosmetics was not confirmed.

    X: Since it was hard and drapeability was insufficient, the face cover was not attached to the head. Further, when the detached clothes were observed, the adhesion of the cosmetics was somewhat observed.

(Example 1)
L-lactic acid / D-lactic acid copolymer having a melting point of 168 ° C. and MFR1 of 20 g / 10 min, L-lactic acid / D-lactic acid = 98.4 / 1.6 mol% (hereinafter abbreviated as “P1”) ) Was prepared as a core component.

  In addition, an aliphatic polyester copolymer having a melting point of 110 ° C. and an MFR 2 of 36 g / 10 min at 190 ° C. and having an aliphatic diol, an aliphatic dicarboxylic acid and lactic acid as constituents (trade name GSPla manufactured by Mitsubishi Chemical Corporation; , Abbreviated as “P2”) and a polymer (chip) prepared by melt-mixing the following organic peroxide at 190 ° C. was prepared by a compound method. That is, dimethyldi (butylperoxy) hexane (manufactured by NOF Corporation, product name: Perhexa 25B-40, purity 40%, decomposition temperature 125 ° C. in a rapid heating test, as an organic peroxide to the aliphatic polyester copolymer P2. ) Is added so as to be contained at a concentration of 0.2 parts by mass (0.08 parts by mass as an organic peroxide), and the temperature is set to 190 ° C. (Toshiba Machine Co., Ltd., Model: TEM) -37BS). Then, the strand was extruded from a 0.4 mm diameter × 3 hole die. Subsequently, the strand was cooled with a cooling bath, and then cut with a pelletizer to collect an aliphatic polyester copolymer (hereinafter abbreviated as “P3”) as a sheath component. The extrusion rate at that time was 30 kg / h, and the screw rotation speed of the biaxial kneader was 200 rpm.

  The resulting aliphatic polyester copolymer P3 had a crystallization rate index of 1.7 minutes. Moreover, MFR3 in 190 degreeC was 13 g / 10min. The reason why the value of MFR was lower than before the organic peroxide was melt-kneaded seems to be that the viscosity was increased due to crosslinking caused by the organic peroxide. Furthermore, MFR4 in 210 degreeC of aliphatic polyester copolymer P3 was 20 g / 10min, and MFR5 in 230 degreeC was 35 g / 10min.

Further, a master batch containing 20% by mass of talc (TA) as a crystal nucleating agent based on P1 was prepared.
Then, after individually weighing so that the composite ratio of P1 and P3 is P1: P3 = 1: 1 by mass ratio, and 0.5 mass% of talc is contained in the molten polymer of P1. Each is melted at a temperature of 220 ° C. using an individual extruder type melt extruder, and using a spinneret having a cross section of the core-sheath type composite fiber, P1 constitutes the core part and P3 constitutes the sheath part as described above. So as to constitute a single-hole discharge rate of 1.00 g / min.

  After cooling the spun yarn with a known cooling device, it is subsequently pulverized at a traction speed of 2100 m / min with an air soccer provided below the spinneret, and is opened using a known opening device, It was collected and deposited as a web on a moving screen conveyor. At the time of opening, most of the constituent fibers were separated, and no contact yarn and convergent yarn were observed, and the opening property was good. The single yarn fineness of the deposited composite long fiber was 4.7 dtex.

Next, the web was passed through a hot embossing device composed of an embossing roll and a smooth metal roll, and heat treated to obtain a polylactic acid-based long fiber nonwoven fabric having a basis weight of 30 g / m ² . As heat embossing conditions, the surface temperature of both rolls is 90 ° C., and the embossing roll is a circular sculpture pattern with an individual area of 0.6 mm ² , the pressure contact density is 20 / cm ² , and the pressure contact area ratio is 15 % Was used.

Subsequently, the face cover of Example 1 was produced using this nonwoven fabric. That is, a sheet having a width of 40 cm and a length of 40 cm is cut out from the nonwoven fabric, folded back at a length of 20 cm, and both ends in the width direction are heat sealed at a temperature of 120 ° C., a surface pressure of 98 N / cm ² , and a treatment time of 1 second. A heat seal portion having a width of 0.5 cm was formed to produce a bag-shaped face cover. When the heat seal part of the obtained face cover was observed, there was no shrinkage due to heat and it was well sealed.

  Table 1 shows the performance of the face cover made of the obtained polylactic acid-based long fiber nonwoven fabric.

(Example 2)
A face cover was obtained in the same manner as in Example 1 except that the basis weight of the nonwoven fabric was 50 g / m ² .

  Table 1 shows the performance of the face cover made of the obtained polylactic acid-based long fiber nonwoven fabric.

(Example 3)
P1 used in Example 1 was used as the core component.

  Moreover, as an aliphatic polyester copolymer constituting the sheath component, an aliphatic diol, an aliphatic dicarboxylic acid and an lactic acid having a melting point of 110 ° C. and an MFR of 20 g / 10 min at 190 ° C. as constituent components A polyester copolymer (trade name GSPla, manufactured by Mitsubishi Chemical Corporation) was used.

  The same organic peroxide as in Example 1 was added so as to be contained at a concentration of 0.075 parts by mass (0.03 parts by mass as the organic peroxide). Other than that, an aliphatic polyester copolymer (hereinafter abbreviated as “P4”) was collected in the same manner as in Example 1.

  The crystallization rate index of the aliphatic polyester copolymer P4 obtained in Example 5 was 1.3 minutes. Moreover, MFR3 in 190 degreeC was 4 g / 10min. The reason why the value of MFR was lower than before the organic peroxide was melt-kneaded seems to be that the viscosity was increased due to crosslinking caused by the organic peroxide. In addition, MFR4 in 210 degreeC of the aliphatic polyester copolymer P3 of a sheath component was 10 g / 10min, and MFR5 in 230 degreeC was 22 g / 10min.

Further, a master batch containing 20% by mass of talc (TA) as a crystal nucleating agent based on P1 was prepared.
Then, after individually weighing so that the composite ratio of P1 and P4 is P1: P4 = 2: 1 by mass ratio, and 0.5% by mass of talc is contained in the molten polymer of P1 Each is melted at a temperature of 230 ° C. using an individual extruder-type melt extruder, and using a spinneret having a cross section of a core-sheath composite fiber, P1 constitutes the core as described above, and P3 is the sheath. The melt spinning was performed under the condition of a single hole discharge rate of 0.86 g / min.

  After cooling the spun yarn with a known cooling device, it is subsequently pulverized at a traction speed of 2000 m / min with an air soccer provided below the spinneret, and opened using a known fiber opening device, It was collected and deposited as a web on a moving screen conveyor. At the time of opening, most of the constituent fibers were separated, and no contact yarn and convergent yarn were observed, and the opening property was good. The single yarn fineness of the deposited composite long fiber was 4.8 dtex.

Next, the web was passed through a hot embossing device composed of an embossing roll and a smooth metal roll, and heat treated to obtain a polylactic acid-based long fiber nonwoven fabric having a basis weight of 20 g / m ² . As heat embossing conditions, the surface temperature of both rolls is 90 ° C., and the embossing roll is a circular sculpture pattern with an individual area of 0.6 mm ² , the pressure contact density is 20 / cm ² , and the pressure contact area ratio is 15 % Was used.

  Table 1 shows the performance of the face cover made of the obtained polylactic acid-based long fiber nonwoven fabric.

(Comparative Example 1)
Using the above-mentioned L-lactic acid / D-lactic acid copolymer P1, 0.5% by mass of talc (TA) is contained therein, and from a round spinneret, the spinning temperature is 210 ° C., and the single hole discharge amount is 1.67 g. Melt spun at / min. Next, the spun yarn was cooled with a cooling air flow, and subsequently drawn with an air soccer ball at 5000 m / min, which was opened and deposited on a collecting surface of a moving conveyor to form a web. The single yarn fineness of the deposited long fibers was 3.3 dtex.

Next, the web was passed through a hot embossing device composed of an embossing roll and a smooth metal roll, and heat treated to obtain a polylactic acid-based long fiber nonwoven fabric having a basis weight of 30 g / m ² . As heat embossing conditions, the surface temperature of both rolls is 130 ° C., and the embossing rolls are circular engraving patterns with individual areas of 0.6 mm ² , the pressure contact density is 20 / cm ² , and the pressure contact area ratio is 15 % Was used.

  Next, an attempt was made to produce a face cover by the same method as in Example 1, but heat sealing could not be performed. For this reason, a face cover was produced by ultrasonic processing instead.

Table 1 shows the performance of the face cover made of the obtained polylactic acid-based long fiber nonwoven fabric.
The face covers of Examples 1 to 3 were superior in flexibility and texture to the face cover of Comparative Example 1, and were excellent in wearability. In addition, the heat sealing process can be performed satisfactorily and the industrial productivity is good.

Claims (4)

  A non-woven fabric comprising a composite long fiber comprising a polylactic acid polymer and an aliphatic polyester copolymer having a melting point lower than that of the polylactic acid polymer, and the aliphatic polyester copolymer is the constituent fiber. The aliphatic polyester copolymer is composed of an aliphatic diol, an aliphatic dicarboxylic acid, and an aliphatic hydroxycarboxylic acid as a constituent component and is crosslinked. Biodegradable face cover. ^{2. The} biodegradable face cover according to claim 1, wherein the basis weight is 15 to 50 g / m ² , the flexibility is 15 cN or more and 60 cN or less, and the drape coefficient is 0.650 or more and 0.950 or less.   In the crosslinked aliphatic polyester copolymer, the aliphatic diol is 1,4-butanediol, the aliphatic dicarboxylic acid is succinic acid, the aliphatic hydroxycarboxylic acid is lactic acid, and its melting point is a polylactic acid type. The biodegradable face cover according to claim 1 or 2, wherein the biodegradable face cover is at least 50 ° C lower than the melting point of the polymer.   When the composite long fiber is melted at a rate of temperature increase of 10 ° C./min and then subjected to differential thermal analysis at a rate of temperature decrease of 10 ° C./min, there is a temperature decrease crystallization temperature due to the aliphatic polyester copolymer. 4. The crystallization temperature is 75 ° C. or more and 85 ° C. or less, and the composite long fiber has a crystallization heat amount of 20 J / g or more and 30 J / g or less. 5. Biodegradable face cover.